My pup doesn't come with a grey water tank and the sink drains directly to outside. I've only camped once with it so far, so I'm not sure what the protocol is for this. Should I have a bucket to catch any water draining from my PUP and see if the CG offers a place to dump grey water? Last time I barely used it other than for drinking water or rinsing something off. My next vacation will definitely involve using the sink more.